The Fregat upper stage has a flight-proved propulsion subsystem that is based on a single-chamber Lavochkin engine. Four clusters of three 50-N hydrazine thrusters provide attitude control. The Fregat propulsion system powered the Fobos probe to Mars, and the main engine was fitted on nearly 30 interplanetary spacecraft. During its numerous missions, the engine demonstrated the highest reliability under extreme conditions, exceeding technical specifications. This application of proven, in-production hardware ensures high reliability and lower cost for the Fregat upper stage. Fregat operates on UDMH fuel and N2O4 oxidizer, and has a liftoff mass of up to 6,535 kg. The weight at burnout is 950-1,100 kg.. Vacuum thrust is 19.6 kN., and burn time is up to 877 sec. The engine can be restarted as many as 20 times.

R-7 The world's first ICBM became the most often used and most reliable launch vehicle in history. The original core+four strap-on booster missile had a small third stage added to produce the Vostok launch vehicle, with a payload of 5 metric tons. Addition of a larger third stage produced the Voskhod/Soyuz vehicle, with a payload over 6 metric tons. Using this with a fourth stage, the resulting Molniya booster placed communications satellites and early lunar and planetary probes in higher energy trajectories. By the year 2000 over 1,628 had been launched with an unmatched success rate of 97.5% for production models. Improved models providing commercial launch services for international customers entered service in the new millenium, and a new launch pad at Kourou was to be inaugurated in 2011. It appeared that the R-7 could easily still be in service 70 years after its first launch. More...